Origins of the Tagalog People, where are we with this?

Taking over Taal Lake was important not just for its freshwater resources, but also because the Taal Volcano mountain range was the higher ground.  If the Central Luzon speakers (or any other group) would maintain that higher ground, then they can descend down upon the Tagalogs and have the upper hand in battle.  Furthermore, the Tagalogs would be pushed towards the shoreline with their backs against the sea.  The Central Luzon speakers do not have to defeat the Tagalogs on land, they simply have to just push them into the sea where they move slowly, have difficulty defending themselves, the tidal currents jostling them around, and have to deal with the possibility of drowning along with fighting their Central Luzon adversaries.